SCIL nanoimprint solutions: Cost-effective high volume nano structuring of sapphire wafers

Abstract

Patterned Sapphire Substrates (PSS) are commonly used to manufacture GaN LEDs. The micro structures on the PSS enhance GaN growth and increase light extraction resulting in a higher efficiency. Reduction of the structure sizes down to nanometer scale will result in even higher efficiency and lower costs of the PSS. Further, the market is moving towards larger (4" and 6") wafers. The conventional PSS manufacturing techniques (optical lithography and hard stamp nanoimprint lithography (NIL)) do not offer a cost-effective solution for the fabrication of micro or nano PSS on large wafers. Soft-stamp NIL is a promising technology that overcomes most of the disadvantages of optical lithography and hard stamp NIL but also has its drawbacks. In this paper we present how Substrate Conformal Imprint Lithography (SCIL) solves the limitations of soft-stamp NIL techniques and allows sub-10 nm resolution on large, non-flat wafers.